Agnes Magoma displays sweet potatoes at Daraja Mbili market in Kisii County. [Sammy Omingo, Standard]
The popular sweet potato is well known for its great source of fibre, vitamins and minerals such as beta-carotene that acts as powerful anti-oxidants in the human body.
According to Kenya Agricultural and Livestock Research Organisation (Kalro), sweet potato has a number of varieties for both food and feed. Kalro orange fleshed sweet potato are for commercialisation, income generation and health improvement. Sweet potato varieties vary depending on their flesh colour, maturity time and recommended growing areas. Some of the common varieties are Kenspot 1, Kenspot 5, Kabode, Vitaa and Mugande according to Kalro. Festus Omogi grows sweet potatoes on his farm in Siaya County and shares vital lessons.
Land preparation
Choose an area in full sun, till the land and add compost manure to make it fluffy. “You can plant on a flat land or make ridges, let the land warm up before planting,” says Omogi.
Propagation
He says sweet potatoes can be propagated from cuttings or tubers. Propagation from cuttings is possible only when the sweet potatoes remain in the field all through the year. The cuttings should be about 20 to 40 centimetres long, with three to five growth buds. “It is best to take them from the tips of young stems,” he says.
Planting
The sweet potatoes are planted in rows of mounds or ridges raised above the ground. These ridges and mounds can be made by hand or using oxen plough or tractors, for those who can afford. When planting, the sweet potato vine is inserted into the mound or ridges with the buds facing upwards. The vines should be planted at a 45-degree angle and ensure at least two-thirds of the vine is buried inside the soil. Bury slips up to the top leaves, press the soil down gently but firmly, and water well.
Weeding
Once the vines have established and began to spread, weeds should be removed constantly until the sweet potato tendrils have covered the ground, upon which they will largely suffocate the weeds. You can also get rid of the occasional weeds by hand.
Fertiliser Application
According to Omogi, sweet potatoes do not really need fertilisers and will do well in moderately fertile and well-drained soils. Farm manure is okay. A farmer who wants to focus on vine rather than tuber production can use the DAP fertilisers.
Pests
Most sweet potato varieties will give good yields despite pest infestation. The most destructive pest to look out for is the sweet potato weevil. To minimise impact of pests, plant on land where sweet potatoes have not been grown in the past two years. The soil can also be earthed up after every four to six weeks to regulate the weevil build-up.
Harvesting
Depending on the variety, sweet potatoes can be ready after four to six months. The yellow fleshed sweet potato are the slowest maturing and will take up to six months to be ready for harvest. Once ready for harvest, the tubers can still stay in the ground for months. “You will be able to easily identify the larger sweet potato tubers by looking for cracks in the ground. Depending on the sweet potato variety, you can harvest anywhere from 40 to 60 bags of sweet potatoes per acre,” says Omogi.
Market
Since sweet potatoes are widely consumed, Omogi says market is available. He sells his produce in Kibuye Market, Kisumu and other major markets around Siaya.
